This invention relates to highly concentrated pearlizing concentrates with a high content of pearlizing waxes and a low content of emulsifiers and special emulsifier/polyol ester mixtures and to a process for their production.
Pearlizers are a long-established and proven medium for providing cosmetic products with an attractive, rich and interesting appearance. An overview of modern pearlizing formulations was published by A. Ansmann and R. Kawa in Parf. Kosm. 75, 578 (1994). The complex requirement profile these formulations have to satisfy includes such properties as high brilliance, good particle fineness and high compatibility with other auxiliaries, and performance requirements relating to processability. Particularly highly concentrated formulations intended for subsequent processing are expected to combine uniform, good physicochemical stability with low viscosity and flowability. Polyol fatty acid esters are often used as viscosity adjusters in the production of pearlizing concentrates.
There are various known formulations which provide surface-active compositions with the required pearlescence and in which polyol fatty acid esters are used. For example, German patent applications DE 3843572 A1 and DE 4103551 A1 (Henkel) describe pearlizing concentrates in the form of flowable aqueous dispersions which contain 15 to 40% by weight pearlizing components, 5 to 55% by weight emulsifiers and 0.1 to 5 or 15 to 40% by weight polyols. Polyol fatty acid esters, for example, were used in large quantities. They were also used in European patent application EP 0205922 A2 (Henkel). This application relates to flowable pearlizing concentrates containing 5 to 15% by weight acylated polyglycols, 1 to 6% by weight fatty acid monoethanolamides and 1 to 5% by weight nonionic emulsifiers. According to the teaching of European patent EP 0569843 B1 (Hoechst), nonionic flowable pearlizing dispersions may also be obtained by preparing mixtures of 5 to 30% by weight acylated polyglycols and 0.1 to 20% by weight selected nonionic surfactants. Finally, European patent application EP 0684302 A1 (Th. Goldschmidt) proposes the use of polyglycerol esters as crystallization aids for the production of pearlizing concentrates.
Although the pearlizing concentrates mentioned are of relatively high concentration, it has been found that the content of active substances can be further increased, even for low-viscosity flowable formulations.
As crucially relevant prior art, German patent application DE 199211186 A1 (Cognis) discloses highly concentrated flowable pearlizing concentrates with concentrations of at least 55% by weight which contain 25 to 45% by weight selected pearlizing waxes, 25 to 40% by weight nonionic emulsifiers and 0.5 to 15% by weight polyol esters. In these formulations, however, a high percentage content of emulsifiers is required to stabilize the pearlizing waxes. The ratio of pearlizing waxes to stabilizing emulsifiers is also equivalent and, where the concentrates are incorporated in formulations, can lead to incompatibilities with other auxiliaries.
Accordingly, the problem addressed by the present invention was to provide new pearlizing concentrates with a very high content of active substances which would be distinguished by a relatively small content of emulsifiers and by improved processability coupled with high stability and comparable performance in regard to the brilliance of the pearlescence.